# Calculating Nitrogen percentage in food products.

1. Jun 22, 2011

### brobertson89

I am currently working for a food manufacturing company that pack their food with nitrogen gas to increase shelf life. However they have an acceptable limit of how much nitrogen can be within the product. Recently they have had some products that have come close to breaching this limit.

The trouble is they do not know why every so often one item does.

I took 100 samples of the products with two various nitrogen flow rates and it turns out that the deviation in the results of a higher flow rate is quite less then compared to the ones with a lower flow rate. However there still is the one or two randomly high values.

The flow rates i tested were 16 and 14 m^3 / h with a pressure of about 3 bar.

I am really stuck on what it could be. Does any one have any ideas?

2. Jun 23, 2011

### mathman

Off hand I would suggest a careful study of the equipment being used.

3. Jun 23, 2011

### rollcast

Try getting the maintenance dept. to check for pipe blockages or obstructions, we have had this with some lines in the workshop recently

4. Jun 23, 2011

### Drakkith

Staff Emeritus
Are you guys using 100% nitrogen or a mixture of different gases?
Also, what do you mean by "how much nitrogen within the product"? The amount that gets absorbed by the food? The amount in the packaging?

5. Jun 26, 2011

### brobertson89

yes it is 100% nitrogen gas

it is a test of how much is in the packaging, we measure the oxygen percentage in the pack by putting a prob with a seal through the package

6. Jun 26, 2011

### brobertson89

sorry i forgot to mention that we have done this, my other guess is that there may be leakages in the pipe work

7. Jun 26, 2011

### brobertson89

I have decided my next cause of action is to find out whether the packages have holes in them and this is the cause or to see whether the product has defects which are entrapping oxygen and then braking whilst within the packaging, releasing the oxygen.

What do you think, are these possible causes?

8. Jun 27, 2011

### Drakkith

Staff Emeritus
I really don't know, but it sounds like you are either getting too much flow rate or the process is going on for slightly too long, causing more nitrogen to build up. A leak wouldn't let ONLY the oxygen out.